If you’ve encountered a message which states ‘An error has occurred while installing [Football Manager title] (missing app configuration)' when attempting to install [Football Manager title], please shut down Steam and delete this file located at the following location:
C:\Program Files (x86)\Steam\appcache\appinfo.vdf
Once you’ve completed this, launch Steam and attempt to reinstall and run the game.
If nothing above works, please submit a support request stating exactly what you've tried so far, and a member of our team will try to help.